
/**
 * \file main.c++
 * \author Joshua Sayers and Yang Miao
 * \date 9-13-09
 */
#include <cassert>
#include <iostream>


#ifdef TEST
    #include "cppunit/TestSuite.h"      // TestSuite
    #include "cppunit/TextTestRunner.h" // TestRunner
#endif // TEST
// -------
// defines
// -------

#ifdef ONLINE_JUDGE
    #define NDEBUG
#endif

int num; //input
int sum[4]; //resulting primes

int primes[] = /* length = 446 */
{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 
101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 
233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 
383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 
547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 
701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 
877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 
1049, 1051, 1061, 1063, 1069, 1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 
1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 
1429, 1433, 1439, 1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511, 1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 
1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663, 1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733, 1741, 1747, 1753, 1759, 1777, 
1783, 1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 
1993, 1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053, 2063, 2069, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129, 2131, 2137, 2141, 2143, 2153, 
2161, 2179, 2203, 2207, 2213, 2221, 2237, 2239, 2243, 2251, 2267, 2269, 2273, 2281, 2287, 2293, 2297, 2309, 2311, 2333, 2339, 2341, 2347, 2351, 2357, 
2371, 2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423, 2437, 2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531, 2539, 2543, 2549, 2551, 2557, 
2579, 2591, 2593, 2609, 2617, 2621, 2633, 2647, 2657, 2659, 2663, 2671, 2677, 2683, 2687, 2689, 2693, 2699, 2707, 2711, 2713, 2719, 2729, 2731, 2741, 
2749, 2753, 2767, 2777, 2789, 2791, 2797, 2801, 2803, 2819, 2833, 2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903, 2909, 2917, 2927, 2939, 2953, 
2957, 2963, 2969, 2971, 2999, 3001, 3011, 3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079, 3083, 3089, 3109, 3119, 3121, 3137};

/**
 * reads an int into num
 * @param in reference to istream from console
 * @return true if that succeeds, false otherwise
 */
bool read(std::istream &in)
{
	if (!(in >> num))
		return false;
	return true;
}


/**
 * checks if n is prime
 * @param n number to be checked
 * @return true if prime, false otherwise
 */
bool check_prime(int n)
{
	assert(n>=2);
	assert(n<=10000000-6);

	if ((n & 1 && n != 1) || n == 2 ) // n is odd and !1 or =2
	{
		for (int i = 0; i < 446; i++)
		{
			if (n % primes[i] == 0) // if divisible by prime in meta cache
				if (n != primes[i])
				{
					return false; //if not equal to prime divisor, n!=prime
				}
				else
					return true;
		}

		return true;
	}
	else
		return false;
}

/**
 * finds sumation for num and places result in sum[0-3]
 * the value of num is not preserved upon return 
 * @return false if that succeeds, true otherwise
 */
bool eval()
{
	if (num < 8)
		return true;
	assert(num >= 8);
	assert(num<=10000000);

	if (num & 1) // num % 2 == 1
		sum[0] = 3;
	else
		sum[0] = 2;

	sum[1] = 2;
	
	num -= sum[0] + sum[1];
	assert(num%2==0);

	bool finished = false;
	
	for (int i = 0; i < 446; i++) //find 3rd and 4th prime
	{
		if (check_prime(num - primes[i]))
		{
			sum[2] = primes[i];
			sum[3] = num - primes[i];

			finished = true;
			break;
		}
	}

	 if (!finished)
	 {
		//this never happens ever while n<=10,000,000
		assert(false);
	 }

	return false;
}

/**
 * prints the four prime numbers that sum up to num
 * @param out console ostream reference
 * @param impossible returned from eval()
 */
void print(std::ostream &out, bool impossible)
{
	if (impossible)
		out << "Impossible.\n";
	else
		out << sum[0] << " " << sum[1] << " " << sum[2] << " " << sum[3] << std::endl;
}


/**
 * either runs the tests or runs the program
 */
int main()
{
	using namespace std;
	ios_base::sync_with_stdio(false); // turn off synchronization with C I/O
	
    #ifdef TEST
        // ----------
        // unit tests
        // ----------

        CppUnit::TextTestRunner tr;
        tr.addTest(TestCollatz::suite());
        tr.run();
    #else
	//run program

	while (read(cin))
	{
		print(cout, eval());
	}

    #endif
	return 0;
}
